[TYPO3] Hiding Frontend User And Groups for different webpages

[Michael Karrer]

Dear List.

i have a typo3 installation with multible webpages for different 
custommers. Everything works great except that in the Acess field of 
content Items all users see all frontend usergroups. is there a way to 
restrict it to the frontend user/groups of some storage folder.

(I think this is a dumb question and may be easy to answer but please 
help because i already wasted hours to find it.)

Thanks a lot!